Exiting Alda REPL in "server only" mode kills all player processes

[daveyarwood]

🐞 Bug report 🐞

Description

Player processes are supposed to outlive the execution of the Alda client, and they generally do, except, for some reason, in the case of running an Alda REPL in "server only" mode.

Steps to Reproduce

1. In a separate terminal, monitor the state of the player processes by running watch alda ps.
2. Start from a clean state by running alda shutdown to shut down all current player processes.
3. Run alda repl -s to start a REPL server.
4. Interrupt the process.

Expected Behavior

• The REPL server process disappears from the alda ps output.
• The player processes remain alive and continue to be present in the alda ps output.

Actual Behavior

All of the processes die and disappear from the alda ps output.

Environment

Operating system and version: Ubuntu 20.04

Alda version:

$ alda version
alda 2.2.1

$ alda-player info
alda-player 2.2.1
log path: /home/dave/.cache/alda/logs

Health check:

$ alda doctor
(all passing)